From Outscape Wiki
The first time you launch the game, you will need to login to an IDA Games account and link it to your Steam account.
Creating an IDA Games account
- If you haven't yet created an IDA Games account, clicking the 'Create Account' button will open the account sign up page in your web browser
- After completing the account signup process and confirming your email address, you're ready to return to the game to login
Linking your Steam account
- After successfully logging in, you will be asked to confirm that you wish to link the IDA Games and Steam accounts you are logged in to together
- When opening the game from Steam in future, you will be automatically logged in and taken directly to the game lobby
Already created an IDA Games account?
If you've already created an IDA Games account, you should be able to login with those credentials.